515 research outputs found

    Evaluating the spatial transferability and temporal repeatability of remote sensing-based lake water quality retrieval algorithms at the European scale:a meta-analysis approach

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    Many studies have shown the considerable potential for the application of remote-sensing-based methods for deriving estimates of lake water quality. However, the reliable application of these methods across time and space is complicated by the diversity of lake types, sensor configuration, and the multitude of different algorithms proposed. This study tested one operational and 46 empirical algorithms sourced from the peer-reviewed literature that have individually shown potential for estimating lake water quality properties in the form of chlorophyll-a (algal biomass) and Secchi disc depth (SDD) (water transparency) in independent studies. Nearly half (19) of the algorithms were unsuitable for use with the remote-sensing data available for this study. The remaining 28 were assessed using the Terra/Aqua satellite archive to identify the best performing algorithms in terms of accuracy and transferability within the period 2001–2004 in four test lakes, namely Vänern, Vättern, Geneva, and Balaton. These lakes represent the broad continuum of large European lake types, varying in terms of eco-region (latitude/longitude and altitude), morphology, mixing regime, and trophic status. All algorithms were tested for each lake separately and combined to assess the degree of their applicability in ecologically different sites. None of the algorithms assessed in this study exhibited promise when all four lakes were combined into a single data set and most algorithms performed poorly even for specific lake types. A chlorophyll-a retrieval algorithm originally developed for eutrophic lakes showed the most promising results (R2 = 0.59) in oligotrophic lakes. Two SDD retrieval algorithms, one originally developed for turbid lakes and the other for lakes with various characteristics, exhibited promising results in relatively less turbid lakes (R2 = 0.62 and 0.76, respectively). The results presented here highlight the complexity associated with remotely sensed lake water quality estimates and the high degree of uncertainty due to various limitations, including the lake water optical properties and the choice of methods

    Progress on agriculture in the UN climate talks: How COP21 can ensure a food-secure future

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    Agriculture, and consequently food security and livelihoods, is already being affected by climate change, according to latest science from the IPCC (Porter et al. 2014). The IPCC agrees that the world needs to produce at least 50% more food than we do today in order to meet the goal of feeding a projected 9 billion people by 2050. This must be achieved in the face of climatic variability and change, growing constraints on water and land for crops and livestock, and declining wild capture fishery stocks. Although the protection of food security lies within the core objective of the United Nations Framework Convention on Climate Change (UNFCCC) (Article 2), formal arrangements for addressing agriculture within COP21 are unlikely. CGIAR would welcome the strengthening of aspirations for food security through action on mitigation and adaptation within a new agreement. We recognise that the new climate agreement is unlikely to be prescriptive about how adaptation in agriculture is supported and how agriculture might contribute to emission cuts. These issues are addressed within countries’ INDCs and determined at national level

    Redefining the "carrier" state for foot-and-mouth disease from the dynamics of virus persistence in endemically affected cattle populations

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    The foot-and-mouth disease virus (FMDV) “carrier” state was defined by van Bekkum in 1959. It was based on the recovery of infectious virus 28 days or more post infection and has been a useful construct for experimental studies. Using historic data from 1,107 cattle, collected as part of a population based study of endemic FMD in 2000, we developed a mixed effects logistic regression model to predict the probability of recovering viable FMDV by probang and culture, conditional on the animal’s age and time since last reported outbreak. We constructed a second set of models to predict the probability of an animal being probang positive given its antibody response in three common non-structural protein (NSP) ELISAs and its age. We argue that, in natural ecological settings, the current definition of a ”carrier” fails to capture the dynamics of either persistence of the virus (as measured by recovery using probangs) or the uncertainty in transmission from such animals that the term implies. In these respects it is not particularly useful. We therefore propose the first predictive statistical models for identifying persistently infected cattle in an endemic setting that captures some of the dynamics of the probability of persistence. Furthermore, we provide a set of predictive tools to use alongside NSP ELISAs to help target persistently infected cattle

    South-South technology transfer of low-carbon innovation: large Chinese hydropower dams in Cambodia

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    Large dams have been controversially debated for decades due to their large‐scale and often irreversible social and environmental impacts. In the pursuit of low‐carbon energy and climate change mitigation, hydropower is experiencing a new renaissance. At the forefront of this renaissance are Chinese actors as the world's largest hydropower dam‐builders. This paper aims to discuss the role of South–South technology transfer of low‐carbon energy innovation and its opportunities and barriers by using a case study of the first large Chinese‐funded and Chinese‐built dam in Cambodia. Using the Kamchay Dam as an example, the paper finds that technology transfer can only be fully successful when host governments and organizations have the capacity to absorb new technologies. The paper also finds that technology transfer in the dam sector needs to go beyond hardware and focus more on the transfer of expertise, skills and knowledge to enable long‐term sustainable development

    The Role of Agriculture in the UN Climate Talks

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    Agriculture, and consequently food security and livelihoods, is already being affected by climate change, according to latest science from the IPCC. The various strands of work already underway on agriculture within the UNFCCC process can be strengthened and made more coherent. A 2015 climate agreement should reference food production and provide the financial, technical and capacity building support for countries to devise ambitious actions for the agricultural sector. A new climate agreement should be consistent with the Sustainable Development Goal (SDG) proces

    Serological profile of foot-and-mouth disease in wildlife populations of West and Central Africa with special reference to Syncerus caffer subspecies

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    The role which West and Central African wildlife populations might play in the transmission dynamics of FMD is not known nor have studies been performed in order to assess the distribution and prevalence of FMD in wild animal species inhabiting those specific regions of Africa. This study reports the FMD serological profile extracted from samples (n = 696) collected from wildlife of West and Central Africa between 1999 and 2003. An overall prevalence of FMDV NSP reactive sera of 31.0% (216/696) was estimated, where a significant difference in seropositivity (p = 0.000) was reported for buffalo (64.8%) as opposed to other wild animal species tested (17.8%). Different levels of exposure to the FMDV resulted for each of the buffalo subspecies sampled (p = 0.031): 68.4%, 50.0% and 0% for Nile Buffalo, West African Buffalo and African Forest Buffalo, respectively. The characterisation of the FMDV serotypes tested for buffalo found presence of antibodies against all the six FMDV serotypes tested, although high estimates for type O and SAT 3 were reported for Central Africa. Different patterns of reaction to the six FMDV serotypes tested were recorded, from sera only positive for a single serotype to multiple reactivities. The results confirmed that FMDV circulates in wild ruminants populating both West and Central Africa rangelands and in particular in buffalo, also suggesting that multiple FMDV serotypes might be involved with type O, SAT 2 and SAT 1 being dominant. Differences in serotype and spill-over risk between wildlife and livestock likely reflect regional geography, historical circulation and differing trade and livestock systems

    Designing Interactive Displays to Promote Effective use of Evidence

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    Interactive displays are increasing being used to convey information, and are a significant factor in promoting statistical literacy (and illiteracy). Durham University and the House of Commons Library are collaborating to create data visualisations (DV) which will be accessible to politicians, researchers and journalists. The focus of this paper is a DV designed to be useful in the run-up to the 2015 general election. The aim was to assemble a rich resource from multiple sources, and to make it easy for target groups to manipulate data and draw conclusions. We identify important changes to the DV as it evolved over 13 iterations, and draw conclusions about appropriate design processes and validation
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